X-ray generator



Dec. 26, 1950 J. J. vLAcH 2,535,708

X-RAY GENERATOR Filed April 1o, 1948 2 sheets-sheet 1 9m. www N mmm @wwwNW NM Qm, um,

7209/275? @fC/72.72 \f. WHC/fb f v, /n Mz,

Patented Dec. 26, 1950 UNITED STATES PATENT GFFICE X-RAY GENERATOR JohnJ. Vlach, Milwaukee, Wis., assigner to General Electric X-RayCorporation, Milwaukee, Wis., a corporation of New York ApplicationApril 10, 1948, Serial No. 20,199

tion analysis of materials, although, of course,

useful for other and general purposes, as well.

An important object of the present invention is to provide an X-raygenerator structure of compact arrangement and small overall dimensions,thereby facilitating manipulation of the same; a further object being toprovide novel and improved means rendering the apparatus substantiallyshockproof for the protection of the user.

Another important object is to provide an X- ray generating unit adaptedfor operation at relatively high intensity, yet safely insulated for theprotection of the user, the generating unit embodying an X-ray tubehaving an envelope cornprising an insulator formed to embrace and thusaid in insulating a high tension power supply cable used for energizingthe tube; a further object being to provide an improved commutatorconstruction for electrically connecting the power supply cable with theoperating elements of the tube within the cable insulating portions ofthe tube envelope. y

Another important object of the invention is to provide an X-ray tubehaving an envelope comprising an insulator, such as glass, and formingzi;

a relatively deep re-entrant pocket for the reception of a power cable,including improved commutator means for electrically connecting thecable with an interior operating element of the tube upon insertion ofthe cable in the pocket; a further object being to form the commutatoras a plate of insulating material mounted on a conducting stem extendingwithin and outwardly of the envelope, the commutator includingelectrical contact shoes in position to engage and electrically connectwith cable conductors, outwardly of the envelope, upon insertion of thecable in its mounting pocket, whereby to permit said stern to be usedfor the operation of gettering means within the envelope, during thefabrication of the tube, and for short-circuiting and thus inactivatingthe getteringmeans when the tube is placed in service.

Another important object is to provide improved means for circulating acooling liquid in heat exchange relation with the anode element of thetube; a further object being to incorporate the nuid circulatingfacilities in a shockproor housing in which the tube is mounted.

Another important object is to provide an improved shockproof housing ofrelatively simple and inexpensive construction for enclosing an X-raytube of the character described, in order to provide an X-ray generatingunit, the housing and tube, when in assembled relationship, havinginterconnecting ducts for the circulation of a cooling fluid through thehousing and in heat exchange relation with an operating element 0f thetube.

Another important object is to provide an X-ray generator unit of thecharacter described, having an improved X-ray outlet window arrangementaffording minimum absorption of X-rays, and wherein the window isdisposed closely and immediately adjacent the X-ray generating source ofthe tube, whereby rays of maximum intensity may be delivered from theunit when in operation.

Another important object is to provide an X-ray tube in which the anodeportion of the tube comprises a unitary, preferably metal base tted withanode target and closely adjacent X-ray window openings, said base beingsealed in the end of a sleevelike envelope member of insulatingmaterial, such as glass, to form the anode end of the tube; a furtherobject being to form the anode as a generally cup-shaped element, withmeans for sealing the edge or lip of the cup-shaped element with thefacing end of the sleevelilze envelope member; a still further objectbeing to provide a novel guard sleeve adapted to be interlockingly ttedin the cup-shaped element in position to shield the seal againstelectron impingement thereon during the operation of the tube as anX-ray generator.

Another important object is to provide an X- ray tube having an anodestructure of the character mentioned mounted at an end of a sleevelikeenvelope member of insulating material, such as glass, wherein saidenvelope member comprises an outer sleeve portion carrying said anodemember at one end and a deeply re-entrant envelope portion secured tothe outer sleeve portion at the end thereof remote from said anodemember, said deeply re-entrant portion having an inner end tfrminatingwithin and adjacent the anode carrying end of the outer sleeve portion,and carrying sealed thereon a cathode structure embodying an electronemitting element disposed adjacent and in alinement with an anode targetformed on said anode member, whereby said envelope portions provide arelatively deep pocket at the cathode end of the tube for receiving,enclosing, and insulating a cable for delivering tube operating power`to the cathode.

Another important object is to form the electron emitting element of thetube as a filament and to provide improved commutator means within thecable pocket, outwardly of the envelope and adjacent the cathodesupporting end of the re-entrant envelope portion, for electricallyinterconnecting the cable with the lament, said means including a memberfor operi ating gettering means within the envelope and for renderingthe gettering means inactive when the cable is in mounted position incontact with the commutator means.

The foregoing and numerous other important objects, advantages, andinherent functions of the invention will become apparent as the same ismore fully understood from the following description, which, taken inconnection with the accompanying drawings, discloses a preferredembodiment of the invention.

Referring to the drawings:

Fig. l is a sectional view taken through -an X-ray tube embodying thepresent invention, the tube being shown as manufactured and ready forassembly in operating position in its enclosing casing;

Figs. 2 and 3, respectively, are sectional views taken substantiallyalong the lines 2-2 and 3 3 in Fig. l

Fig. 4 is a sectional view taken through .an X-ray generator unitembodying the present invention and incorporating the tube shown in Fig.l; and

Figs. 5 and 6 are enlarged sectional views, respectively, takensubstantially along the lines 5-5 and 3-5 in Fig. 4.

To illustrate the invention the drawings show an X-ray generator unit ii comprising an X-ray tube I2 and a casing or housing i3 in which thetube is mounted and enclosed in service.

The tube i2, as shown more particularly in Figs. l-3 of the drawings,comprises an anode structure i4, and a cooperating cathode structure i5enclosed in sealed and evacuated envelope 's means i3. As shown, theanode structure i4 preferably comprises a frame or base Il, as of metal,forming a generally cup-shaped element sealed to the envelope means andforming a part thereof. bottom i3 and cylindrical walls i9 enclosing acavity 23, an anode target element or button 2i being mounted preferablycentrally on the bottom of the cup-shaped element, with a target surface22 facing into the cavity 23.

f The cathode assembly preferably comprises a head 23 forming a disk ofmetal supported in spaced apart facing alineinent with respect to theanode target surface 2i. To this end, the head 23 may be supported on astem 24 which, in turn, extends through and is mounted centrally in thebottom of a seal member 25, by means of which the member 24 and thecathode structure supported thereon is sealed to and supported on theenvelope structure i5. The cathode structure also comprises an electronemitting element, shown as a lament 23, mounted on, extending between,and electrically connected with conductor stems 2l' supported on thehead 23, the filament 26 being thus carried in spaced registration withrespect to the target surface 22. The stems 2l are supported on,insulated from, and extend through the head 23, as by means ofinsulating sleeves 28 mounted in channels formed through the head, andby insu- The cup-shaped member has a lated clamps 29 supported on thehead 23 or the stem 24 behind the head, that is to say, the side thereoffacing away from the anode target surface 2|.

The envelope means i6 preferably comprises a member of insulatingmaterial, such as glass, having an outer sleevelike portion 3U, to oneend of which the anode member I4 is sealed, as by means of a sealingsleeve 3l of metal adapted to seal with glass. The sleeve 3| at one endis sealingly secured to the lip or rim of the cup-shaped anode member,as by a welded or brazed seal 32, the opposite end edge of the sleeve 3iforming a glass-to-metal seal 33 with the end of the outer sleeveportion 3E] of the envelope member. The envelope member I6 alsopreferably includes an inner re-entrant sleeve portion 34, integral withand secured to the outer sleeve portion 30 at the end thereof remotefrom the anode member I1, said re-entrant or inner portion 34 extendingwithin the outer portion 35i adjacent the anode connected end of saidouter portion, the terminal edges of the inner portion forming aglass-tometal seal 35 with the rim of the cup-shaped cathode supportingmember 25, which preferably comprises metal readily scalable with glass.

It will be seen from the foregoing that the envelope means IS Vcomprisesthe glass member having outer and inner portions 30 and 34, the fcup-shaped anode member IT sealed to the end of the outer envelopeportion 33, and the cupshaped cathode supporting and sealing member 25,sealed in the end of the inner envelope portion 34. The envelopeportions 3U and 34 also form a deep, cylindrical, double wall pocket 36,the bottom of which is defined by the cathode support member 25, saidcylindrical pocket 35 opening at the anode and cathode remote ends 31 ofthe glass envelope member.

If desired, the walls I9 of the anode member l? may be formed with anannular groove 38 inwardly of and adjacent the seal 32, and a sleevelikeshield 39', having a locking bead '40) at one end and longitudinal slits4! extending from said beaded end in the material of the sleevelikemember, may be mounted on the anode member by interlocking the beadedend 40 thereof in the locking groove 38, whereby the sleeve member 39may be mounted in position to screen the glassto-metal seal 33 from thestray electrons and other energized particles emitted by the anode orcathode when the device is in operation. The cathode, likewise, mayembody a sleevelike element 42 mounted on and carried by the cathodehead 23, encircling the same and enclosing the space between said headYand the cathode mounting element 25, said sleevelike element 42 havinga terminal skirt 43 embracing and enclosing the cup-shaped member 25 andthe glass-to-metal seal 35, in order to protect said seal against thedeleterious action of stray electrons or other energy particles. Ifdesired, the sleevelike member 42 may be extended beyond the head 23 inthe direction of the anode target 22 in order to provide a focusing cup44 for the electron emitting element 26.

The cathode mounting stem 24 extends through and is sealed, as at 45, ina preferably central opening in the member 25. Outwardly of said centralopening, the member 25 is formed with openings 46 disposed about thecentral opening and sealingly fitted each with a sleeve 4l of materialreadily scalable with glass. Conductor members 48 and 48 of metalreadily sealable with glass are mounted coaxially within the sleeves 41,

sealed therein, and insulated therefrom by sealing globules 49 of glasssurrounding and sealed to the stems 48 and 4B', within and sealed to thesleeves 4l. The conductor stems 48 and 4S thus extend inwardly andoutwardly of the sealed envelope means It. The inner ends of a pair ofstems 48 are electrically connected, respectively, with the lament stems2, as by means of flexible connecting conductors 5t. outwardly of theenvelope, said pair of stems 48 are each connected with a correspondingconductor wire 5|. The inner end of another of said stems 48 may beelectrically connected with one end of a gettering member 52, comprisinga hollow conductor containing evaporable gettering material, such asbarium or the like, said gettering member extending in the spaceenclosed by the sleeve 4Z between the head 23 and the cathode mountingand sealing member 25, the remote end of said gettering member beingelectrically connected with the stem 24, as at 53. The outer end of thestem 48 may be electrically connected with a Ilexible conductor 5 l twill, of course, be understood that X-ray tubes iunction to produceX-rays in response to the activation of the anfde member by impingementthereon of electrons emitted by the cathode. Operation of the tube as anX-ray generator, including electron impingement upon the anode, resultsin the generation of large quantities of heat within the envelope, andparticularly at the anode. In conditioning an X-ray generator foroperation, it is necessary to remove not only all of the gas that may bepresent within the envelope, but also all occluded gas contained in theanode and cathode and in the material of the envelope itself. Ir" suchoccluded gases are not entirely removed, they will be gradually releasedthin the envelope and impair the exhausted condition at which thegenerator is designed to operate. Removal of occluded gases may beaccomplished by baking or otherwise heat treating the entire tube at atemperature short of the toning point of the glass portions thereof,while maintaining the interior of the envelope under vacuum conditions,and also by heating the electrode elements of the tube to a hightemperature, either by operating the cathode for electron bombardment ofthe anode, or by placing the electrodes in a magnetic ield iluctuatingat radio frequency.

The envelope, for tube conditioning purposes, may be connected with asuitable molecular exhaust pump, as by connecting the envelope with thepump by means of a connection, as at 5d, at the junction 3! of the outerand inner en.- velope portions 3@ and 34.

Ait-er all of the occluded gases and impurities have thus been removedfrom the envelope, the exhaust connection may be sealed oi to form aglobular' seal 55. As a nal step of the tube conditioning process, thegettering means may be operated by passing an electric currenttherethrough to heat the same, in order to volatilize or ash thegettering material and release it in vapor form in the space within thesleeve 42, between the cathode head 23 and the cathode mounting elementrlhis space, it will be noted, communicates with the interior of theenvelope through the annular channel defined between the skirt and theseal 35. The vaporirotion of gettering material, such as barium, withinthe sleeve 42 will form innocuous end products through the combinationof any gases, remaining within the envelope, with the metallic 6.gettering vapor which, after combining with any residual gases, becomesdeposited as a permanent lm upon the interior of the sleeve 42.

Operation of the electron emitting lament 26, in conditioning the tubefor service, may be accomplished by applying filament energizing' powerbetween the conductors 5l. Operation of the gettering element 52 may beaccomplished by applying an electrical potential bet-.veen the conductor5i and the portions of the stem 24 which project outwardly of theenvelope, within the cavity 35. The outwardly projecting end of the stem24 may be provided with an axially extending, internally threadedopening 5S in its end to facilitate the attachment and electricalconnection thereto of a suitable conductor for power applic-ation duringthe gettering operation.

After the tube has been completely conditioned for service, theconductors Ei and 5i may be cut ofi approximately opposite the outwardlyprojecting end of the stern and the gettering connection with said outerend of the stem may be removed and discarded, and a connectingcommutator 5d may be assembled on the outwardly projecting end of thestem. This cominutator, as shown more particularly in Fig. 5 of thedrawings, preferably comprises a plate or disk adapted to be mounted onthe outwardly projecting end of the stem as by means of a headed screw58 adapted to be secured in the threaded opening The plate 5l preferablycomprises insulating material having a centrally disposed socket 5Sopening on one side i'or receiving the end of the stem Eli. On its otherside, the plate is preferably formed with an annular rib disposedconcentric with respect to the axis of the socket 58', said rib dening acentral seat adapted for the reception of a preferably cup-shapedcommutator member 6l, which may be held in place by the head of th screw53.

One oi the conductors 5i and, if desired, the conductor 5I', also, mayextend through a duct E2 formed in the disk 5l and electricallyconnected, as by soldering or otherwise, with the cup-shaped commutatormember Si. Outwardly of the rib ESG, the disk Eil forms a seat for anouter annular commutator ring 63 which may be secured to the head 5l lasby means of screws or other suitable fastening means. The otherconductor 5i may extend through a duct 64 and. be electricallyconnected, as by soldering or otherwise, with the commutatol member B3.The head 5l of insulating material thus electrically isolates thecommutator ring 53 and the conductor 5i connected therewith from theinner commutator member Ei and the conductors electrically connectedtherewith.

It should be noted that, since the gettering member 52 is 'electricallyconnected at 53 with the stein 24, the connection of the conductor 5|with the inner commutator member 6l, which is electrically connectedwith the stem 2t by the screw 58, serves to connect the other end of thegettering element with the stem' 2f?, and thus completely inactivate thegettering member. If, during the service life of the tube, it shouldbecome necessary to operate the gettering member, the conductor 5i maybe disconnected from the commutator member El and the gett'eringoperation may be performed by applying electrical potential between theconductor 5i and the commutator member i, which is electricallyconnected with the stem 24.

It will be seen that the commutator assembly Y affords means for makingelectrical connection with the lament 28, and that it is disposed withinand substantially at the bottom of the envelope cavity or pocket 38.rThe walls of the pocket are preferably cylindrical and of uniforminternal diameter from the commutator 59 to the open end 8'? of thepocket; and the pocket is adapted to receive and enclose a power cable85 for supplying operating power to the cathode. This cable preferablycomprises at least a pair of conductors 95 enclosed in suitableinsulation and adapted, respectively, to be electrically connected withthe filament conductors 5|. To this end, the cable is preferablyenclosed in an insulating sleeve 97 of relatively rigid material, whichmay comprise ceramic, plastic, o-r other self-supporting insulationmaterial, the external dimension of the sleeve 8l being such as to allowfree insertion thereof within the pocket 36.

At its distal end, the sleeve 8l is formed with a cavity providing aseat 98 :'n which is mounted a disk 69, preferably of insulatingmaterial having a central portion forming a seat 'E8 for a prefer ablymetal nut 'i l, which, as shown, is secured in the seat 'E9 as by meansof a holding screw l2, to whch one of the cable conductors 68 is elecmtrically connected. This nut forms a mounting' for one end of apreferably helical spring member i3, the other end of which supports andelectrically contacts with a ring forming a contact shoe M. The diskmember 89 also forms a seat 'i5 cencentrically around the seat 58, inwhich seat is mounted a support ring "i6, which is secured in place asby means of one or more set screws il mounted through the cable sleeve8l and taking radially into the ring i8, thereby holding the ring andthe disk 69 in the distal end of the cable sleeve 6l. The ring i9 iselectrically con neet-ed with the other of the cable conductors 89 andforms a mounting for one end of a preferu ably helical spring 78, theother end of which supports and electrically connects with a ring i9forming a contact shoe.

The springs 73 and 18 are disposed concentriu cally the one within theother, and project from the distal end of the cable sleeve 6l inpositionsupporting the annular shoes lli and 'i9 yieldingly in coaxialalinement and equal spacement from the d'stal end of the cab-le sleeveSi. The contact shoes 'M and l@ are of electrically com ductingmaterial, and are thus electrically conN nected through the springs i8and i8 and the mounting members '|I and "i8, respectively, with theconductors 69 of the cable. Upon insertion of the cable sleeve 5T intothe cavity 89, the shoes M and 18, respectively, Will be brought intocontact and yieldingly held, respectively, against the commutatormembers 6| and 83, whereby, 'as the result of insertng the cable sleevein the pocket 39, the cable conductors 66 will become electricallyconnected with the conductors 5| and hence with the lament 28.

As shown more particularly in Figs. 4-6 of the drawings, the housing I3comprises an outer, preferably cylindrical shell 88 of metal, havingexternal screw threads at one end for threaded engagement with a ring 8|forming a retaining gland, having a cylindrical internally threadedportion for engagement with the threaded end of the housing member 8eand an inturned annular retaining flange 82. At its opposite end, thecylindrical shell is provided with internal screw threads 88 forthreaded connection with a mounting collar 84. Said collar is adapted toreceive and support a mounting ring therein in concentric alinement withthe end of the tubular member 88, set screws 86 being provided forsecuring the ring 85 in the collar 81|. -The ring 85 carries a sleeve 8lshaped substantially in conformity with the external shape of the outerglass portion of the envelope of the X-ray tube, said sleeve extendingwithin the member 88 to entirely enclose the envelope portions 38 withinthe casing member 88. The ring 85 also supports a sleeve 88, whichextends axially outwardly thereof and encloses the outwardly projectingportions of the sleeve B1. This sleeve 88 also encloses the entire anodeend of the X-ray tube, and carries a cover cap member 89 at thevterminal end of the sleeve 88.

VThe anode member Il is provided with a cavity 98 communicating with theside of the anode member 2| opposite from the target surface 22, saidcavity 9|) opening at the bottom of the member l1 in a direction awayfrom the target member. The anode member l1 also is provided withpreferably threaded bolt openings 9| disposed around the cavity 90. Thecover cap member 89 includes a portion adapted to seat upon the end ofthe anode member and a portion adapted to extend into the cavity 89behind the target member 2|, said portion being provided with a duct 92adapted to open upon the back of the target member 2|. Suitable capscrews 93 may be provided in the cap member 89 in position tothreadingly engage in the bolt holes 9| in order to secure the capmember 89 upon the end of the anode member The cap member is alsoprovided with a duct 94 opening therein upon the cavity 9U at one sidethereof. These ducts 92 and 91| communicate, respectively, with radiallyextending channels 92 and 94 formed inthe cap member 89, said radialducts, respectively, communicating with longitudinal ducts 95 disposedin ribs 98 formed on opposite sides of and along the sleeve 88 from thehead 89 to the collar 85. These ducts 95 communicate each with anoutwardly opening seat 91 formed in the ring 85 to receive inlet andoutlet fittings 98 for connection with a suitable supply of coolingfluid, the collar 86 surrounding the ring 85 being provided withopenings opposite the seats 91 to allow for the assembly of the fittings98 therein through the collar 88.

Cooling liquid may thus be introduced through one of the fittings 98,thence through a semicircular duct 99, in the ring 85, and through oneof the ducts 95 to and through the ducts 92 and 92', and delivered inthe space immediately behind the target member 2|, to thereby cool thesame. Cooling liquid may thence circulate from the chamber 90, throughthe connected ducts 98 and 9E', and one of the ducts 95, to the outletfitting 98.

The cooling arrangement thus is exceedingly simple and readilydemountable for access to the anode end of the tube, this facility, inpart at least, resulting from the novel arrangement of the entire anodeend of the tube as a sleevelike member having the partition wall I8carrying the target member 2| and dividing the anode member into thegenerating and cooling chambers 29 and 98 on opposite sides of theintegral partition i8. When the tube is in operation as an X-raygenerator, electrons emitted by the cathode element 29 will impinge athigh velocity upon the target surface 22 and constitute the same as asource of X-rays, in accordance with well known principles. X-rays thusgenerated at the target 5 surface 22 will be transmitted radially of thetube and may pass outwardly thereof through windows |50, which maycomprise panes of any suitable X-ray pervious material set into andsealed in openings formed in the sleevelike walls of the anode memberIl', said windows being disposed closely adjacent the peripheral edgesof the target member 2|, preferably on opposite sides thereof as shown.

Electron impact upon the target member results in the generation ofexcessive heat whereby the temperature of the target element,particularly at the target surface 22, may approach the meltingtemperature of the material at the target surface, the higher theintensity of electron bombardment of the target surface, the higher thetemperature to which it will be raised when the device is in operation.The present invention affords most eicient yet simple means formaintaining the temperature of the target member within limitspreventing or minimizing the destructive action of electron bombardmenton the surface 2|, by providing for the delivery and circulation of acooling fluid immediately behind and in direct heat exchange contactwith the target element 2|. As a-conseouence, the Xray generator may beoperated at much higher electrical pressure for the generation .of highintensity X-rays without destroying the target.

As shown more particularly in Fig. 4 of the drawings, the cable issecured in place within the socket or cavity 3b by mounting it on thehousing i3. To this end, the sleeve 6'?, within which the end of thecable is mounted. preferably comprises insuating material and is formedwith an outstanding rm lil at its end remote from the connecting'commutatcr saidl rim extending outwardly ofthe end 3i andi seal 55 ofthe tube envelope when the saine are in mounted position within thehousing I3. The marginal edge of the rim IEl may be tted with a collar|02 of electrical conducting material sized to slidinglv fit within theend of the sleeve portion 8S of the housing. rlhis rim provides meansfor clampingly securing a preferably cylindrical bushing |93 of anysuitabe insulating material to and in concentric alinement with themember BI, in position extending outwardly of the housing I3 through theclamping gland 8|, the bushing |533 embracing and encircling the cable doutwardly of the housing. To this f end, the bushing m3 has anoutstanding iiange |533 to which the collar to2 may be clampinglysecured, as by means of bolts IfiZ. The bushing H33 thus may be used asa convenient handle for manipulating the end of the cable when insertingit in the cavity 36.

The cable prcferabiy includes an outer sheath IM of electricalconducting material, such as woven wire, an extension I of which ispreferably clamped between the bushing flange il and the rim collar |532in electrical contact therewith through the bolts |512', making contactwith the clamping gland i I, whereby said cable sheath IM iselectrically connected with and grounded upon the housing i3. The entirecable end assembly may be held in the housing lil by means of theremovable clamping gland Si, the resilience of the springs 'i3 and "ieof the commutator assembly serving to yieldingly press the cable endassembly in one direction against the inturned flange of the clampinggland, while at the same time urging the Contact shoes 'it and i9 in theopposite direction against the contact members t! and It will be seenfrom the foregoing that the apparatus of the present invention isadapted for easy assembly and disassembly. The cable may be mounted andremoved merely by inserting or withdrawing the same and manipulating theclamping gland 3| to secure the cable end in place or to permit of itsremoval from mounted position in the housing. The cable thus may beapplied or removed without disturbing the rest of the assembly. Afterthe cable has been removed, it is likewise possible to dismount theX-ray tube from the housing merely by removing the bolts 93 andwithdrawing the tube axially from the housing' through its open endwhich normally carries the clamping gland 8|. Removal of the X-ray tubethus may be accomplished without disturbing the assembly otherwise thanby removal of the cable and the clamping gland 8|. The structure of theX-ray tube itself, including the novel anode structure and also thestructure and srrangement of the commutator assembly 59, greatlyfacilitates the fabrication of the generator.

It is thought that the invention and its numerous attendant advantageswill` be fully understood from the foregoing description, and it isobvious that numerous changes may be made in the form, construction andarrangement of the several. parts without departing from the spirit orscope of the invention. or sacrificing any of its attendant advantages,the form herein dis- `closed being a' preferred embodiment for thepurposeof illustrating the invention. i

The invention is hereby claimed as follows: l. The combination of X-reytube including a sea-led envelopehaving a metal anodehead fj rmi-og anend of said envelope. said head comprising a sleeve-like side wall and amedial partition, integral with said side wall, means sealing said sidewall in said envelope, at one end of said head. said pirtition having acentral opening therein providing a seat facing the opposite end of thehead, a target block sealed in said seat and closing said opening, saidblock forming an electron target facing into said envelope, an electronemitting cathode in said envelope in posin tion facing said target, andmeans forming an X-ray pervious window in said side wall at the junctionthereof with said partition, a housing for receiving said X-ray tube,said housing having a sleeve-like portion snugly enclosing the sidewalls of said anode head, said sleeve-like portion being formed withiiuid inlet and outlet channels extending longitudinally therein, and aremovable cover sealed on the envelope remote end of said head to form acavity therein, in which cavity the back of said target block isdirectly exposed, said removable cover being formed with ducts thereinfor connecting said cavity with said channels or the circulation oftarget cooling fluid into and out of said cavity.

2. rlhe combination as set forth claim l, including removable fasteningmeans for securing said cover on said head, said cover and housinghaving interengaging means for anchoring the tube in said housing whensaid cover is secured on said head.

3, In an X-ray tube, a sealed envelope having a sleeve-like glassportion and a metal anode head forming an end of said envelope, saidhead comprising a sleeve-like side wall, in alinement with saidsleeve-like glass portion, and a bottom wall forming an anode targetfacing into the envelope, an electron emitting cathode, in saidenvelope, in position facing said target, said side wall of said anodehead having an X-ray pervious window formed therein at the' juncturethereof -with said bottom wall, means- Vforming a peripheral glass-metalseal sealingly connecting said sleeve-like side wall with the end ofsaid sleevelike glass portion, and a shield for said seal comprising ametal sleeve having an end secured on and within said sleeve-like wallof said anode head, between said window and said seal, and extendingthence outwardly of said head, Within the sealed end of. saidsleeve-like glass portion, in position underlying said peripheral sealand extending between said seal andV said anode.

4. An X-ray tube, as setr forth in claim 3, wherein said shield isformed with spring fastening means at one end thereof and the side wallof the anode head is formed with an inwardly opening keeper notch tolatchingly interiit with said fastening means to hold said shield inplace on said head in seal shielding position.

5. An X-ray tube, as set forth in claim 3, wherein said shield is formedwith spring fastening means at one end thereof and the sidewall of theanode head is formed with an inwardly opening keeper notch to latchinglyintert with said fastening means to hold said shield in Iplace u on saidhead in seal shielding position, said side wall of the anode head beingformed also with an inclined cam surface over which said fastening meansmay ride to depress same for entry into said notch.

6. An X-ray tube comprising sealed envelope means, including a glassmember having an outer and a re-entrant inner. sleeve portion, sealedtogether at one end: of theV member. and presentingConcentrcallydisposed sealing ends at the oppositev end ofA the member,4an anode comprising a metal cup member having a rim sealed. to thesealing end of said outer sleeve member, means forming an anode targeton the bottom of said cup member, a cup-shaped metal seal member having;sleeve-like walls and sealed to the sealing end of the re-entrant sleeveportion, said metal seal member having a bottom formed with a centralopening, said inner sleeve portion of the envelope forming a pockethaving a bottom at said metal seal member and opening at the re mote endof Said inner sleeve portion, a cathode structure embodying an electronemitter, a mounting stem supporting the cathode structure in theenvelope with the emitter in position faoing said target, said stemextending through said central opening in the bottom of said metal sealmember and being mounted and sealed on said metal seal member at saidopening, and extending into said pocket, a terminal block supported Vonsaid stem in said pocket, and emitter leads connected with the emitterwithin the envelope and extending into said pocket, through giass sealsformed in the bottom of said seal member, in position for connectionwith contact means on said terminal block.

JOHN J. VLACH.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,261,708 Coolidge Apr. 2, 19181,949,347 Bouwers Feb. 27, 1934 1,967,869 Coolidge July 24, 19342,347,424 Machlett Apr. 25, 1944 FOREIGN PATENTS Number Country Date162,842 Switzerland Aug. 29, 1931

